

import java.sql.Time;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.prefs.Preferences;

public class Main {
    public static void main(String[] args) {
        StringBuffer a=new StringBuffer("A");
        StringBuffer b=new StringBuffer("B");
        op(a,b);
        System.out.println(a+","+b);
    }
    public static void op(StringBuffer x,StringBuffer y){
        x.append(y);
        //y=x;
    }
}
